Bis(bioreductive) alkylating agents: synthesis and biological activity in a nude mouse human carcinoma model.

Chemical investigations leading to the construction of bis(bioreductive) alkylating agents having both conformationally restricted and mobile spacer regions are described. Two targets having the conformationally mobile ethylene spacer group, namely, 2,2'-ethylenebis[6-(hydroxymethyl)-p-benzoquinone] diacetate (3b) and 2,2'-ethylenebis[6-(bromomethyl)-p-benzoquinone] (3c), were studied in vivo and in vitro using an established epithelial/Burkitt lymphoma hybrid cell line (D98/HR1) previously shown to induce carcinomas in nude mice. Inactivity of both test compounds in vitro, the relative resistance of these cells to test drugs in vitro, and the selective antitumor properties of the bis(bromomethyl) analogue in vivo lead to the proposal that this compound undergoes bioreduction to an alkylating species in the hypoxic core of the tumor, thereby exerting its action.

Clinical significance of the 1-hour biopsy in renal transplantation.

Biopsy specimens were obtained from 43 transplanted kidneys at the time of excision from the donor but prior to revascularization, and 1 hr after revascularization. Two independent laboratories evaluated specimens by immunofluorescent techniques for the presence of IgM, IgA, IgG, C'3, and fibrin. Results from the two laboratories examined for reproducibility and immunological specificity, and correlated with clinical course. Results show that immunoglobulin deposition seen in the 1-hr renal biopsy specimens is of little significance, because: (1) immunoglobulin deposition was difficult to quantitate reliably, (2) the presence of immunoglobulins did not correlate with clinical course, and (3) the majority of immunoglobulin deposition detected was not immunologically specific, since it was most often either present prior to vascularization or disappeared with vascularization.

Reduction in ventilator response to CO2 with relaxation feedback during CO2 rebreathing in normal adults.

BACKGROUND: Previous studies have shown that relaxation biofeedback reduced time on the ventilator for the difficult-to-wean patients. OBJECTIVE: To test the hypothesis that the underlying mechanism of biofeedback ventilator weaning was the reduction of neural respiratory drive (NRD). DESIGN: Prospective, linear regression analysis. SETTING: Critical care medicine department in tertiary health care hospital. SUBJECTS: Fifteen healthy adult volunteers were randomly assigned to the biofeedback group, and 15 healthy adult volunteers were randomly assigned to a control group. INTERVENTIONS: Relaxation feedback was administered while a single variable, PaCO2, was inputted to the respiratory control system and the output measured. While rebreathing 7% CO2/93% O2, the biofeedback group received a baseline session and a relaxation feedback session and the control group received a baseline session and a no feedback session. MEASUREMENTS AND RESULTS: During relaxation feedback, there was a significant (p < 0.001 to p < 0.05) reduction in the slope of minute ventilation (VI), mean inspiratory flow (VT/TI), occlusion pressure in 0.1 s from onset of inspiration (P100), respiration rate (RR), and diaphragm (DA) EMG compared to baseline. We also found the above breathing parameters decreased significantly for relaxation feedback (p < 0.001-0.05), compared to baseline, at maximum end-tidal CO2 (64 +/- 1.2 mm Hg) (all data are expressed as mean +/- SE). The decrease for VI = -4.65 +/- 1.17 L/min, DA EMG = -0.4 +/- 0.21 microV, P100 = -1.13 +/- 0.56 cm H2O, VT/ TI = -144 +/- 82.91 ml/s, and RR = -3.1 +/- 0.79 breaths/min. No significant changes occurred in these parameters for the control group. CONCLUSIONS: We conclude that the addition of the behavioral input of relaxation feedback results in decreasing the values of respiratory parameters that reflect NRD.

Antivascular endothelial cell antibody--its role in transplantation.

Sera samples from eight different groups of patients were tested for the presence of circulating antibody (IgG) directed against vascular endothelial cell antigens. The indirect immunofluorescent method which used either whole blood vessels or single endothelial cells as targets was compared to lymphocytotoxicity panels. The indirect immunofluorescent antibody test (IFA) consistently detected antibody in sera samples which were negative for lymphocytotoxic activity, and the presence of IFA antibody to vascular endothelial cells had a much better correlation with both clinical course and renal allograft rejection than did the lymphocytotoxicity panels. Single vascular endothelial cells appeared to be a more sensitive target for the detection of IFA antibody than did whole vessels. Preliminary absorption studies suggest that cell-specific as well as HL-A antigens play a role in the immunological response to vascular endothelial cells.

Stress-related impairments in cellular immunity.

The percentages of total T-lymphocytes (OKT-3+), helper T-cells (OKT-4+), and suppressor T-cells (OKT-8+) were significantly lower in blood samples obtained from 40 medical students during examinations, compared to baseline values obtained 6 weeks earlier. In addition, the response of T-lymphocytes to stimulation by phytohemagglutinin and concanavilin A was also significantly lower during examinations, compared to baseline. Self-report data documented significantly greater distress associated with examinations. The data have implications for immunosuppressive disorders and stress-related illnesses.

The reduction of weaning time from mechanical ventilation using tidal volume and relaxation biofeedback.

We sought to determine if biofeedback could reduce weaning time for the hard-to-wean patient by improving important weaning factors that are not effectively dealt with by present weaning methods. These include respiratory muscle electromyograph (EMG) efficiency, respiratory drive, and the anxiety of the ventilator-dependent patient. After the patient had received mechanical ventilation for 7 days and the day weaning began (start), the patient was randomly assigned to biofeedback or to the control group. There were 20 patients assigned to each group, with mean ages of 60.2 (biofeedback) and 59.3 (control) yr. The patients assigned to the biofeedback group received daily, until extubation or being placed on no resuscitation status (termination), frontalis electromyographic (EMG) relaxation feedback for anxiety reduction and improved respiratory muscle EMG efficiency, tidal volume/diaphragm EMG (VT/DAP), and VT feedback for increasing VT and respiratory drive defined as tidal volume/inspiratory time (VT/TI). The control group was visited daily to control for attention and reassurance. The results showed a significant (p less than 0.01) reduction in mean ventilator days for the biofeedback group of 20.6 +/- 8.9 SD compared with 32.6 +/- 17.6 SD mean days for the control group. From start to termination, there was a significant (p less than 0.01) increase in baseline VT, from 295 +/- 41 to 415 +/- 45 ml, and a significant (p less than 0.02) increase in VT/DAP, from 0.33 +/- 0.09 to 0.94 +/- 0.22 L/mV for the biofeedback group but no significant change in these parameters for the control group.(ABSTRACT TRUNCATED AT 250 WORDS)

Identification of a region of the Epstein-Barr virus (B95-8) genome required for transformation.

In a previous study the identification of a region(s) of the Epstein-Barr virus (EBV) genome, which is associated with transformation, was attempted by marker rescue. A transforming EBV was rescued from D98/HR-1 hybrid cells, which contain the non-transforming HR-1 EBV genome, after transfection with specific BamHI and Charon 4A fragments (J. Stoerker and R. Glaser, Proc. Nat. Acad. Sci. USA 80, 1726-1729, 1983). In this study, characterization of the EBV DNA in four human lymphoblastoid cell lines (LCL) transformed with rescued virus was performed. It was found that recombination between the transfected fragments, BamHI H,F,X and the Charon 4A fragment (EB-26-36) which is equivalent to the BamHI H,F,X region, and the endogenous HR-1 EBV genome in the D98/HR-1 cells took place. This recombination resulted in the formation of transforming EBV. The EBV DNA in the four LCLs are similar to each other and to HR-1 EBV DNA. However, the EBV DNA in all four LCLs also contain the U2 region plus additional sequences of B95-8 DNA. The U2 region is deleted in HR-1 EBV DNA which is associated with HR-1 cells and the D98/HR-1 hybrid cells. Thus, transforming activity of the HR-1-like viruses rescued from D98/HR-1 cells was concomitant with the recombination of the 0.26-0.36 region of the EBV genome, suggesting that this region is necessary for at least the initiation of transformation.

Stress, loneliness, and changes in herpesvirus latency.

This study used a prospective design to examine the influence of examination stress and loneliness on herpesvirus latency as measured by changes in antibody levels to three herpesviruses, Epstein-Barr virus (EBV), Herpes simplex type I (HSV-1), and cytomegalovirus (CMV). Three blood samples were obtained from 49 first-year medical students, with the first sample drawn 1 month before final examinations, the second on the first day of final examinations, and the third during the first week after their return from summer vacation. A median split on the UCLA Loneliness Scale divided subjects into high- and low-scoring loneliness groups. There were significant changes in the antibody titers to all three herpesviruses across the sample points, with the lowest levels found in the third (low stress) sample. High-loneliness subjects had significantly higher EBV antibody titers than low-loneliness subjects. These data suggest that stress-related immunosuppression can significantly modulate herpesvirus latency.

Stress and the transformation of lymphocytes by Epstein-Barr virus.

Although various stressors appear to influence herpesvirus infections, the underlying mechanisms have not been studied. A prospective design was used to examine the effects of examination stress and loneliness on the transformation of B lymphocytes in mixed cultures of T and B lymphocytes by Epstein-Barr virus (EBV). Three blood samples were drawn from 42 EBV-seropositive medical students, with the baseline sample taken 1 month before their final examinations, the stress sample drawn on the first day of final examinations, and the third sample taken the first week after their return from summer vacation. A median split on the UCLA Loneliness Scale divided the subjects into high- and low-scoring loneliness groups. There were significant effects for change over trials, with the lowest transformation levels (i.e., more virus required to transform cells) found in the stress sample. There was also a significant main effect for loneliness, in which high loneliness was associated with lower transformation levels. Possible immunological pathways for the observed changes are discussed.

Herpesvirus saimiri immortalized gamma delta T cell line activated by IL-12.

IL-12 is a novel heterodimeric cytokine important for the regulation and differentiation of lymphocytes and NK cells. Like other cytokines, IL-12 mediates its biologic activity through high-affinity receptors expressed on responsive cells. To date, a large number of receptors for IL-12 have been found only on PBMC following activation with PHA or IL-2. To gain further knowledge of the IL-12R complex and the IL-12 signal transduction pathway in cytotoxic T cells, we studied a number of human T cell lines that had been transformed to permanent growth with Herpesvirus saimiri, an oncogenic virus of nonhuman primates. This paper reports the expression of IL-12R on a human gamma delta T cell line that responds to IL-12 with enhanced cytolytic activity and increased expression of cytolytic effector molecules granzyme B and perforin. Using these T cells as a model of IL-12 signal transduction, we confirmed that these events involve members of the Janus kinase family of nonreceptor tyrosine kinases JAK2, TYK2, and signal transducer and activator of transcription 4.

Changes in Epstein-Barr virus antibody titers associated with aging.

Antibody titers to the Epstein-Barr virus (EBV), early antigen (EA) IgG, and virus capsid antigen (VCA) IgG and IgA, were measured in 44 geriatric subjects to determine if the depression in cellular immunity known to be associated with aging affects the expression of latent EBV. Similar assays were performed on plasma obtained from a young adult (medical student) population as a control group. We found that 89% of the geriatric samples were positive for EA IgG, and 83% of the plasma obtained from medical students were positive for EA IgG. One hundred percent of the geriatric subjects were positive for VCA IgG, and 87% of the medical students were positive for VCA IgG. Seven percent of the medical student blood samples were positive for VCA IgA; in contrast, 36% of the blood samples obtained from the geriatrics subjects were positive. Significant differences were also found in the geometric mean titers (GMT) of antibodies to EBV antigens; the GMT to EBV EA and VCA were significantly higher in the geriatric group. The data suggest that there may be some loss of control over latent EBV by the cellular immune response in geriatric individuals.

Modulation of cellular immunity in medical students.

This study assessed the psychosocial modulation of cellular immunity in 34 medical-student volunteers. The first blood sample was obtained 1 month before examinations, and the second on the day of examinations. There were significant declines in the percentage of helper/inducer T-lymphocytes, in the helper/inducer-suppressor/cytotoxic-cell ratio, and in natural killer-cell activity in the blood samples obtained on the day of examinations. Half of the subjects were randomly assigned to a relaxation group which met between sample points; the frequency of relaxation practice was a significant predictor of the percentages of helper/inducer cells in the examination sample. Three biochemical nutritional assays (albumin, transferrin, and total iron-binding protein) were within normal limits on both samples. Data from the Brief Symptom Inventory showed significantly increased global self-rated distress associated with examinations in the no-intervention group, compared to nonsignificant change in the relaxation group. Clinical and theoretical implications are discussed.